1. Field of the Invention
The present invention relates to a dead bolt assembly, and more particularly to a dead bolt assembly for a tubular door lock.
2. Description of the Prior Art
Various kinds of tubular door locks have been developed and widely used, some of which are disclosed in the following U.S. Pat. Nos.: 4,639,025 to Fann et al., filed Mar. 17, 1986, entitled "ADJUSTABLE DEAD BOLT ASSEMBLY"; 4,804,216 to Marotto, filed Feb. 1, 1988, entitled "CONVERTIBLE BACKSET LATCH MECHANISM"; 4,850,626 to Gallego, filed Mar. 2, 1988, entitled "IMPROVED LATCH BOLT WITH SELECTIVELY VARIABLE DRIVING PIN DEPTH"; 4,890,871 to Lin, filed Nov. 17, 1988, entitled "TUBULAR DOOR LOCK WITH AN ADJUSTABLE DEVICE FOR SETTING THE DEAD BOLT"; 4,927,195 to Wu et al., filed Nov. 8, 1988, entitled "DUAL BACKSET DEADBOLT ASSEMBLY"; and 4,927,199 to Wu et al., filed Sep. 23, 1988, entitled "LATCH ASSEMBLY FOR CYLINDER LOCK". In these patents, the configurations thereof are complicated and can further be simplified such that the manufacturing fees thereof can be decreased.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional tubular door locks.